Tulkas was the most warlike of the Valar and the last of them to descend into Arda, coming to the aid of the others when he heard of their war with Melkor. Melkor fled before him, and the Spring of Arda was begun.

After the Two Lamps were erected and the Valar had made their first dwelling at Almaren, Tulkas wedded Nessa in a great feast. Being weary and content he slept, and Melkor decided his hour to retaliate had come.

Tulkas is described as delighting in wrestling and contests of strength. He wielded no weapon, and rode no steed. As he cared little about either past or future, he was not a good councillor, but nonetheless a very hardy friend. He is described as being slow to wrath, but also slow to forgive—for that reason, he was one of the Valar that opposed the release of Melkor.